Power control for fluid motors



March 13, 1951 w, G sc u 2,545,051

POWER CONTROL FOR FLUID MOTORS 1 Filed Dec. 4, 1947 2 Sheets-Sheet 1 VDP IN VEN TOR.

CUa/Ler 6. Scfiuif ATTORNEYS.

March 13, 1951 w. cs. SCHUTT 2,545,051

POWER CONTROL FOR FLUID MOTORS Filed Dec. 4, 1947 2 Sheets-Sheet 2 IN V EN TOR.

ATTORNEYS.

Patented Mar. 13, 1951 POWER CONTROL FOR FLUID MOTORS Walter G. Schutt, Adrian, Mich., assignor to Stearns Manufacturing Company,

Adrian,

Mich., a corporation of Michigan Application December 4, 1947, Serial No. 789,613

4 Claims.

This invention relates to power control for fluid motors. It is the object of the invention to control the acceleration and deceleration of one or more fluid (particularly hydraulic) operated motors automatically by the travel of a moving part of the motor or a part moved by the motor.

In some automatic machines it is desirable to alter the speed of movement of one or more of the parts during a portion or portions of the stroke. The apparatus, which is the subject matter of this application, accomplishes this desirable end in a very simple and efficient manner.

In the drawings:

Fig. l is a side elevation, partly in section, showing the apparatus.

Fig. 2 is a diagrammatic View of the variable displacement pump showing it in position of minimum displacement.

Fig. 3 is a similar view showing the same pump in position of maximum displacement.

Fig. 4 is a side elevation showing the apparatus connected with two motors.

Fig. 5 is a side elevation showing a modified form of the apparatus in which the piston is stationary and the cylinder moves.

Fig. 6 is a plan view showing several motors successively operated from the one variable displacement pump.

VDP is a variable displacement pump which has a, pipe connection I which leads to a pressure relief valve 2 in pipe 3. 4 is a four way valve in the main which delivers the fluid alternately to each end of the motor cylinder M. These valves can be operated by hand, or operated by a moving part of the motor or some other part of the machine to reverse the motor, when this is in order, in accordance with the plan of operation of the parts of the machine. The piston 1 moves crosshead 8 on which is located a cam 9 which is adapted to depress crank arm H] which is attached to shaft II which has a crank I2 which connects by link [3 with crank arm I4 that operates the cam I5 of the control for the variable displacement pump. The cam follower button [6 is part of slide H on which is carried shaft IS on which the rotor I9 of the variable displacement pump is rotatively supported. This rotor is provided with a plurality of vanes 20 which in a familiar way project from the rotor and withdraw into the rotor, as the rotor rotates through one revolution. The displacement of the pump in Fig. 2, is the minimum displacement and in Fig. 3, is a maximum displacement. This is a variable volume pump and the position of the rotor determines the volume of liquid that is pushed through the pump at each revolution.

Of course, the greater the volume pushed through per revolution the more liquid that passes into the motor and the faster the piston will travel; Any other variable displacement pump can be utilized. Such as, a multiple piston type of Wobble plate variety.

The surfaces of cam 9 are so inclined that they depress or allow the cam following roll lever 2| to rise in both the forward and rearward movement of the cam and piston. Fig. 4 shows that more than one crank arm is located on the crank shaft II. There is the crank arm l0 shown in Fig. l and also another crank arm 22 which is attached to another crosshead 25 which is behind the crosshead 8 of the motor cylinder M. This crosshead is moved by a piston 21 in motor M1.

Fig. 6 shows three motors actuated by the one variable displacement pump. The motor M has the cam 9 and crank arm 10 and contact roller 2|. The motor M1 has the crank arm 22 and cam 24. The motor M2 has the cam 25, the crank arm 26 and contact roller 21. All the crank arms are attached to the crank shaft l I which connects with the slide I! which shifts the rotor of the variable displacement pump by means of the cranks l2, l4, and link l3, cam l5, and button I6. The valves which lead to each motor cylinder are shown in Fig. 6, to wit: valves 28, 29 and 35. These valves are opened in succession in theoperation of the machine by cams 31, 32 and 33, on a common crank shaft 34.

Fig. 5 shows a modified form of construction in which a motor cylinder M4 travels and the piston 35 is stationary and connected by piston rod 36 with stationary shaft 31. This motor cylinder M4 travels along the piston and operates a crank 38 which turns the crank shaft 39 to do the necessary work. A cam 49 is on the motor cylinder and travels with the motor and operates the crank arm 4! to turn the crank shaft 42. The same arrangement of multiple cylinders and cams each controlling a separate crank arm to control the shaft 42 can be used. Crank shaft 42 can control the variable displacement pump in the same way as shown in Fig. 1.

What I claim is:

1. A fluid operated system in which a variable volume of fluid is furnished to one or more motors to control the speed of the piston in moving to do useful work, which comprises a variable displacement pump with means to alter the fluid displacement of the pump, a plurality of motor cylinders and pistons with pipe connections between the said pump and each end of each motor cylinder including a reversing valve for each cylinder that reverses the flow of fluid from end to end of the cylinder, a separate cam operated by a moving part of each motor or mechanism operated by motor, operating connections between each cam and the means for altering the displacement of thepump in response to the contour of the cam as the cam moves in response to actuation from the motor, a fluid main with branches leading to each motor cylinder and with the said reversing valve in each branch, a cut off valve in each branch to each motor and cam mechanism for successively opening each cut off valve and successively connecting each motor cylinder with the variable displacement pump.

2. A fluid operated system in which a variable volume of fluid is furnished to one o'r'more motors to control the speed of the piston in moving. to do useful work, which comprises a variable displacement pump with means to alter the. fluid; displacement of the. p, a lur l t oi mo or c linders and pistons with pipe connections between the said pump and each end of each motor cylinder including, a reversing valve for each cylinder that reverses the flow of fluid from end toend of the cylinder, a separate cam operated by a moving, part of each motor or mechanism operated by motor, a crank shaft provided with crankswhich are operated by the cams on the several motors, said Gran shaft having an actuating connection Witha means for altering the displacement of the pump in response to the contour of the cam as the cam moves in response. to actuation of the motor, a fluidmain with branches leading to each motor cylinder and with the said reversing valve in each branch, a cut off valve in each branch to each motor and cam mechanism for successively opening each cut off valve and successively connecting each motor cylinder with the each cam and the means for altering the displacement of the pump in response to the contour of the cam as the cam moves in response to actuation from the motor, a fluid main with branches leading to each motor cylinder and with the said reversing valve in each branch, a cut off valve in each branch to each motor and mechanism for successively opening each out 01f valve and successively connecting each motor cylinder with the variable displacement pump.

4. A fluid operated system in which a variable volume of fluid is furnished to one or more motors to control the speed of the piston in moving to do useful work, which comprises a variable displacement pump with means to alter the fluid displacementof the pump, aplurality of motor cylinders and pistons with pipe connections between the said pump and each end of each motor cylinder including a reversing valve for each cylinder that reverses the flow of fluid from end to end of the cylinder, a separate cam operated by a moving part of each motor or mechanism operated by motor, operating connections between each cam and the means for altering the displacement of the pump in response to the contour of the cam as the cam moves in response to actuation from the motor, a fiuid main with branches leading to each motor cylinder and with the said reversing valve in each branch, a out 01f valve in each branch to each motor and cam mechanism for successively opening each, cut off valve and successively connecting each motor cylinder with the variable displacement pump-,said cam mechanism comprising a rotatable shaft with a plurality of cams for tripping and opening successively each ofsaid out 01f valves,

WALTER G. SCHUTI.

REFERENCES CITED,

'11he following references, are of. record in the file of this patent;

UNITED STATES PATENTS Number Name Date 1,799,113, Miedbrodt Mar. 31, 1931 2,192,778. Stacy- Mar.- 5, 1940 2,228,700 Hamner et a1. Jan. 14, 1941 2,416,360 Waldie V Mar. 4, 1947' FOREIGN PATENTS N umber Country, Date 12 L793 Great'Britain Apr. 10, 1919 

